Running the examples

The OpenSceneGraph has an ever growing number of examples available for developers to learn from. Following is a guide to getting these examples running.

Once the OpenSceneGraph is installed you will need to place the location where it was installed on the system paths environmental variables. Also download the demo data and set the OSG_FILE_PATH environment variable so that the example datasets can be found by OSG. It is probably worth setting your autoexec.bat, .bashrc, .tcsh, etc to pick up on these settings so that next time you log in everything is in easy reach. Below are examples for the different platforms on how to set up your environment. The examples are not built by default, use the cmake utility and set the option to enable building of the example applications. To build them, run cmake with the following parameter: -DBUILD_OSG_EXAMPLES=1

Windows:

set PATH=path;C:\OpenSceneGraph\bin
set OSG_FILE_PATH=C:\OpenSceneGraph-Data;C:\OpenSceneGraph-Data\Images

All the examples run from the command-line. Most require parameters to be passed, such as what file to load. If you are in any doubt just run the application and it will either run, or provide help on what options it accepts. You can also print out full help my running the example with the option --help.

To run the examples in quick succession on Windows, use the runexamples.bat script which can be found in the the root of the OpenSceneGraph distribution:

./runexamples.bat

Press Escape to close each application and move on to the next application.
On Unix, you should be able to use

sh ./runexamples.bat

Brief introduction to the examples

Demonstrates the use of osg::AnimationPath for setting up animations for transform nodes and the usage of osg::OverlayNode. Three overlay modes can be specified as argument:--overlay or --object OBJECT_DEPENDENT_WITH_ORTHOGRAPHIC_OVERLAY--ortho or --orthographic VIEW_DEPENDENT_WITH_ORTHOGRAPHIC_OVERLAY--persp or --perspective VIEW_DEPENDENT_WITH_PERSPECTIVE_OVERLAY

Demonstrates the use of the compositeviewer. -1 Single view with fountain.osg and a statshandler and trackballmanipulator-2 Two views each on a different screen sharing the same scene. First view trackballmanipulator and statesetmanipulator. Second view statshandler, trackballmanipulator and a pickhandler.-3 Three views within a single window. Window and graphics context manually created. First view (left bottom) with several event handlers. Second view (right bottom) with a trackballmanipulator and a pickhandler. Third view (upper half) with cessnafire.osg and a trackballmanipulator.

Demonstrates the use of deep vs shallow vs custom copying of scene graphs. A specialized CopyOp class is used to output all copying that takes place when performing a deep or shallow copy. This example allows for quick experimentation (in source) with the different CopyOp flags.

The hang glide demo creates a simple flying site (Don Burns local hang glide site in fact!), demonstrating how to create simple terrain, trees and skydomes, and how to implement a simple flight camera manipulator to allow the user to fly around.

An example of how to set up planar reflections using the standard multi-pass stencil buffer algorithm. This is all handled within the scene graph, so there is no need to hardwire multi-pass effects into your own application.

An example of how to decorate your scene graph geometry for useful effects such as scribing. This demo uses two instances of your model, the first one uses the state values set in your scene graph, the second instance override the polygmode to render it as wireframe, and with a polygon offset to ensure it is seen from all angles. These two instance are grouped together and then are treated like any other scene graph.

An example of use node maks to select different parts of the scene graph for different traversals, in this case two separate images are drawn for the left and right eyes to generate a stereo 3D image from two flat images!